They do look for CARB EOs, that's why Cali is such a bitch. It varies from place to place, but most smog stations won't even touch your car unless everything that doesn't look stock has a CARB EO to go with it. If you don't pass the visual inspection, they won't even bother with the sniffer test. If there's an EO or part that's questionable, they may send you to the BAR ref. The BAR ref will definitely find anything that's not CARB legal, even if it's a single vacuum line out of place. Cali is cracking down on fraudulant smog stations, so even the run-of-the-mill smog stations are getting more strict. We're also supposed to be switcthing from visual inspections and emissions testing to dyno testing sometime soon. You're right though, any setup can pass an emissions test as long as it's not horribly out of tune, and your cat is in good working order and properly warmed up, but you can still fail the visual.

 

Wet is not necessarily always better without a SC either...